1. Field of the Invention
The present invention relates to an image forming device, an image forming method, and a program product. In particular, the invention relates to an image forming device capable of replacing any of a plurality of toner cartridges, an image forming method of forming image using said toner cartridges, and a program product for controlling said image forming device.
2. Description of the Related Art
A color printer has a plurality of toner cartridges and switches the toner cartridges in sequence to complete the developing process. In the field of this kind of printers, a toner cartridge rotary movement type color printer is known wherein a plurality of toner cartridges are loaded into a rotatable cartridge holding unit to be presented rotationally so that toners of various colors can be adhered to a photoconductor drum in sequence.
On a conventional toner cartridge rotary movement type color printer, when toner in a toner cartridge is almost gone and the toner cartridge becomes empty, a user is notified of the condition and prompted to replace the cartridge. When the user enters a command into the printer requesting to remove the toner cartridge that is empty, the particular toner cartridge is moved to a specified replacement position (e.g., Unexamined Publication No. JP-A-10-78740). Also known is a color printer (“LP-1500C”, produced by SEIKO EPSON CORPORATION) wherein a toner cartridge is automatically moved to a specified replacement position when the toner cartridge becomes empty.
In case of the printer disclosed by the above mentioned Unexamined Publication No. JP-A-10-78740, the toner cartridge that is empty and needed to be replaced is moved to the replacement position only when the user operates the operating panel unit. However, since the cartridge holding unit of the printer rotates in one direction only, there is a problem that it takes a long time to move the empty toner cartridge to the specified replacement position.
On the other hand, on the printer (“LP-1500C”, produced by SEIKO EPSON CORPORATION) that automatically moves an empty toner cartridge to the replacement position, printing cannot be executed until the toner cartridge that is located at the replacement position is replaced when an empty toner cartridge exists. However, it often happens that a small amount of toner is remaining in the toner cartridge even though it is detected to be empty. In such a case, the user cannot quickly acquire printed matters of particular urgency even though there may be usable tone left in the cartridge, making it inconvenient and also uneconomical as the toner cartridge with some toner remaining has to be replaced.